Does anyone know if the bottom row of key caps (Ctrl-Windows-Alt etc.) on a Cherry G80-8200HPDUS-2 keyboard would be compatible with a das keyboard (or Filco) style keyboard?

That is, are the MX stems mounted in the Center, or off-Center?

I was thinking about trying to get one and use the keycaps, but I wasn't sure they would work.

Thanks;

Yes, they are standard 1.25 key compatible with any other Cherry MX board that use them on bottom row. Caps lock is fulltouch with center stem as well so you can use that too. I used same series of g80 to supply my Poker.
You had mixed up with the MY8000, only those are off center bottom row and not ever doubleshots either.

> only those are off center bottom row and not ever doubleshots either.

Yes, I learned that the hard way. I bought a used G81-8000HPBUS-2 thinking it was almost perfect for what I had planned.

I then discovered that the Bottom row (in this area) wouldn't fit my MX keyboard and also wasn't double-shot.

And, I had incorrectly assumed that the keycap profile would match my existing ones, so I could mix and match without an issue.

Instead, I was sad...

Most of the 8113, 8200, and similar models from the MX8000 series often have the ISO enter so many people end up needing to get something like a cheap MY8000HPBUS for the enter and \| keys so you should be all set either way.